Machine latch guard



Aug. 20, 1968 R. BLOOD ErAL 3,397,555

MACHINE LATCH GUARD Filed Aug. 17, 1965 6 Sheets-Sheet 1 Aug. 20, 1968 R. BLOOD ETA!- 3,397,555

MACHINE LATCH GUARD Aug. 20, 1968 R. BLOOD 3,397,555

MACHINE LATCH GUARD Filed Aug. 17, 1965 6 Sheets-Sheet 5 Aug. 20, 1968 R. BLOOD ETAL MACHINE LATCH GUARD 6 Sheets-Sheet 4 Filed Aug. 17, 1965 g- 0, 1968 R. BLOOD El AL MACHINE LATCH GUARD Filed Aug. 17, 1955 6 Sheets-Sheet 5 FIG 8 R. BLOOD mm. 555

MACHINE LATCH GUARD Aug. 20, 1968 Filed Aug. 17, 1965 6 Sheets-Sheet 6 50L W W\ I13; I 51..-: I 1 56 57 56a l United States Patent 3,397,555 MACHINE LATCH GUARD Raymond Blood, Shepshed, and Ernest Start, Raddington, England, assignors to William Cotton Limited Filed Aug. 17, 1965, Ser. No. 480,340

Claims priority, application Great Britain, Aug. 20, 1964,

Claims. (Cl. 66-88) ABSTRACT OF THE DISCLOSURE A straight bar knitting machine in which a bar of alternate frame needles and a bar of remaining frame needles are cam operated and selected by control means to operate together for plain knitting and for one bar of frame needles to operate with cam operated and spaced loop spreader machine needles for rib knitting, and having a latch guard for each machine needle to ensure that new yarn kinks fall from the sinkers on to the hook side of the latches, together with means securing the latch guards in fixed relation to the machine needles, such as by rivetting or securing in the same tricks as the machine needles, and a loop spreader element being also secured such as by rivetting or being integral with the latch guards.

This invention is for improvements in or relating to straight bar knitting machines and concerns means for adapting a straight bar plain knitting machine for also knitting rib fabric and for automatically changing between plain and rib fabric.

Our (US. Patent No. 3,050,967 provides in the plain machine a bar of spaced machine needles with which there is associated loop spreader elements, these spaced machine needles matching with predetermined of the bearded frame needles, which are rendered ineffective for rib knitting, and the loops of the spaced machine needles being spread by the spreader elements and then pierced by said predetermined frame needles to change from rib knitting to plain knitting.

During the rib knitting in this arrangement the yarn sufficient for the spaced machine needles and their cooperating frame needles is in a specific embodiment first fed to all the frame needles and on the sinker noses, but said predetermined frame needles between said co-operating frame needles are caused, such as by beard pressing points, to cast off their yarn kinks, and as the sinkers retract, these yarn kinks fall off the sinker noses onto the spaced frame needles which proceed to knit the yarn kinks into loops.

According to a specific embodiment of said patents the spaced machine needles are bearded needles and in order to ensure pressing of the machine needle beards satisfactorily between their old loops and their new yarn kinks, our US. Patent No. 2,978,889 provides for special separating elements parallel to the machine needles and having upper abutments and special operating means therefor by which the new yarn kinks are pushed behind the beards.

It is now proposed to use a bar of latch needles as the spaced machine needles, because once the old loops and new yarn kinks are disposed at opposite sides of the latches this is a manner of separation which in normal circumstances would not be expected to require special separating elements as in the instance of bearded needles.

However it has been found that, at least when slack loops are being formed, there is a tendency for at least some of the new slack yarn kinks to fall from the sinker noses at the wrong side, i.e. the old loop side of the latches so that these yarn kinks are cast off without forming the desired new loops.

An object of the invention is to avoid the tendency to casting off of new yarn kinks, particularly when they are slack yarn kinks, by comparatively simple means.

The invention provides a straight bar plain knitting machine having spaced machine latch needles for enabling rib fabric to be produced, means for advancing the machine latch needles during which their latches are opened, and a latch guard for each machine latch needle to ensure that new yarn kinks, particularly when they are slack for forming slack loops, fall from the sinker noses onto the open latches. Conveniently the latch guards are in the form of blade elements secured in the same tricks on the machine needle bar as the spaced machine needles. The latch guards may be integral with loop spreader elements or secured to the needles.

The invention also provides the combination in a straight bar knitting machine of machine needles of latch needle type and each having a wide shank and steppeddown stem, a loop spreading element for each machine needle and adapted for spreading a loop hanging rearwardly from the stem of each machine needle, and a latch guard adapted to ensure that loops falling from sinker noses fall onto the hook side of the machine needle latches.

According to a subsidiary feature of the present invention the frame needle bar which was previously of unitary form, is of split needle bar form with suitable control mechanism for the two bars so that those frame needles which are not required to knit during rib knitting are at that stage held down out of operation.

The above and other features of the invention set out in the appended claims are incorporated in the construction which will now be described, as a specific embodiment with reference to the accompanying drawings in which:

FIGURE 1 is a general cross sectional view of a Cotton's patent straight bar knitting machine having yarn control means according to the invention.

FIGURE 2 is a general front view of the machine.

FIGURE 3 is an enlarged perspective view of part of the machine needle bar showing yarn control means.

FIGURE 4 is a detail view of a machine needle showing the yarn control means in a modified form.

FIGURE 5 is a detail view of yarn looping elements in the machine at a stage of the frame needles drawing new yarn off the sinkers.

FIGURE 6 is a perspective view of looping elements in the machine at a stage of transferring machine needle loops to frame needles.

FIGURE 7 is a sectional view of part of the machine showing a modified frame needle bar arrangement.

FIGURE 8 is a side view of part of the modified needle bar arrangement.

FIGURE 9 is an enlarged partial side view of FIG. 7.

Referring to FIGURE 1 the straight bar plain knitting machine shown is of the Cottons patent type comprising a row of bearded frame needles 1 carried by a frame needle bar 2 and having usual knitting movements imparted to it by usual cam operated mechanism such as represented by a link connection 3 to a cam follower lever 4 having a cam follower 5 operated by a cam 6 on the machines usual main cam shaft 7. There is also the usual row of sinkers 8 operable by usual jacks 9 and slurcock 10 from usual Coulier mechanism not shown in this figure for convenience, and by usual catch bar 11 operable by a cam follower lever 12 having a cam follower 13 engaging a cam 14 on the shaft 7. Usual thread carrier means is also not shown for convenience. Usual knocking over bits are indicated at 114, usual knocking-over slides are indicated at 15 and usual narrowing head is indicated at 16. Usual operating means for these parts 14, 114, and 16 are not designated since they are not relevant to the invention.

Although this machine is basically a plain knitting machine, it is provided with a machine needle bar 17 as and for the purpose (of also making rib fabric) disclosed in said US. Patent No. 3,050,967 to which reference is directed for full details.

However instead of the machine needles being bearded needles, as particularly described in the latter Patents, the present machine needles 18 are latch needles. The needle bar 17 is operated with substantially the same movements as disclosed in the latter patents and by substantially the same means comprising an arm connection 19 to a cam follower lever 20 having a cam follower 21 engaging a cam 22 .on the shaft 7, and a link connection 23 to a cam follower lever 24 having a cam follower 25 engaging a cam 26 on the shaft 7.

As shown in FIGURE 2 the machine is of Inulti-section type, being composed of six knitting section AF and a central control section G. In this figure is also indicated the usual Coulier mechanism 34, and a punched chart programming control represented at and which is substantially as disclosed in our US. Patent No. 3,141,316 to which reference is directed for full details. Although this control is basically for programming courses and fashioning motions, which is irrelevant to the present invention, it also controls incidental mechanisms in the machine such as for example a usual top disc shaft which is hereinafter referred to in connection with the present invention.

Referring to FIGURE 3, the machine needle bar 17 is formed with a longitudinal groove 17a and a plurality of transverse slots or tricks 17b for locating the machine needles, and a top plate 17c is secured by screws such as at 17d to the bar 17 in a position in part overlying the machine needles 18 to retain them in position.

Each machine latch needle 18 has a wide strip shank 18a which extends into the associated slot 1711, a down wardly projecting locating butt 18b which fits in the groove 17a, a narrow stem 18, a hook 180. on the stem 18c, and a latch 18e pivoted on the stem 180.

Each machine latch needle has an associated latch guard 27 and a loop spreader 28.

In the embodiment of FIGURE 3 the latch guard 27 and loop spreader 28 for each needle are integrally formed with a strip shank 29, see particularly FIGURE 5, similar to the machine needle shank 18a and fitting alongside the latter to extend therewith into the associated slot 1712, the shank 29 also having a butt 29a similar to the machine needle butt 18b fitting in the groove 17a.

Each latch guard 27, see particularly FIGURE 5, is of narrow strip form and has a rear portion 27a extending level and in face engagement with an upper portion of its associated needles shank 18a, and an intermediate portion 27b which inclines from the front end of the rear portion 27a out of the vertical plane of the latter substantially into a vertical plane with its associated needles stem 180, with the latch guard proper 27 extending from the front end of this intermediate portion 27b horizontally forwards substantially in the needles vertical plane to a front end 27c which is slightly inclined downwardly and rearwardly and which is disposed a short distance above the tip 18 of the needles latch 18e when the latter is in fully open position as shown.

In the embodiment of FIGURE 3 the rear strip portion 27a is integral with an upper part of the rear shank portion 29, and in the embodiment of FIGURE 4 the rear strip portion 27a is secured by rivets 27a to the machine latch needle shank 18a.

Each loop spreader 28, see particularly FIGURE 5, is of narrow spring strip form and has a rear portion 28a extending level and in face engagement with a lower portion of its associated needles shank 18a, and the looper spreader proper extends forwardly from the portion 28a and is cranked laterally outwards from the needle stem 4 180, whereat it extends horizontally forwards and terminates in an inturned tip 28!) which engages in a recess 18g in the side of the needle stem.

In this embodiment of FIGURE 3, the loop spreader 28 is formed integral with a lower portion of the shank 29. In the embodiment of FIGURE 4 the rear portion 28a of the loop spreader is secured to the needle shank 18a by rivets 28c.

The machine is operated substantially as disclosed in said US. Patent No. 3,050,967, and as shown in FIGURE 5, when during rib knitting the kinks such as K of newly fed yarn fall off the sinkers 8, particularly if they are of slack form for a slack course, any tendency for the kinks to fall to the rear of the open latches 18a is avoided by the provision of the latch guards 27 which would be engaged by the kinks and would deflect them onto the latches 182 at the hook side thereof.

Thus it is assured that the new yarn kinks K will be held separate from the oldloops such as at 0L and will be thereof satisfactorily drawn by the machine latch needles 18 through the old loops OL.

At the change over from rib knitting to plain knitting, the machine latch needles 18 have the required additional forward movement imparted to them, as described in the latter patents, by the cam 22, and as a result the needle steps, indicated at 1811 in FIGURE 6, incline the old loops OL forwardly at the top, and the loop spreader elements 28 spread the loops to be received by the rising frame needles for the transfer as described in said latter patents.

In said latter patents, the frame needles are carried by a untiary frame needle bar, so that new yarn is fed to all the frame needles when rib knitting, there being also provided miss press points for pressing off the yarn kinks of alternate frame needles so that these yarn kinks fall off the sinker noses onto the machine needles.

In a modified arrangement particularly for use with the present machine latch needles, the frame needle bar is of split needle bar form. That is to say, as shown in FIGURE 7, there is a main frame needle bar 30 carrying alternate of the frame needles 1, and an auxiliary needle bar 31 carrying the other alternate frame needles 1.

The main needle bar 30 is caused, through the aforesaid arm connection 3 to the cam operated mechanism 4-6, to always have the usual knitting movements imparted to it. However the auxiliary frame needle bar 31 is mounted alongside the main bar 30 for relative vertical movement in a slideway formed by end plates such as indicated at 32 secured by bolts such as 33, FIGURE 8, to the ends of the main bar 30, and having vertical inturned edges such as 32a engaging in vertical end grooves 31a in the auxiliary bar 31, and the main bar 30 having vertical slots such as 30a allowing for vertical movements of securing bolts 34 projecting from the auxiliary bar 31. The auxiliary bar 31 is spring biased upwardly by springs such as at 35, FIGURE 8, extending between the main bar 30 and a bracket 36 secured to the auxiliary bar 31, said bracket having a shoulder 36a engaging an adjusting screw 37 secured to the main bar 30 to act as adjustable limit stop means.

For effecting the relative vertical movement of the auxiliary bar 31, the bar has lower bracket means 38, FIG- URE 7, carrying a peg 39 which engages in an end slot 40 in a short lever 41 which is pivoted by a pivot pin 42 to the needle operating arm 3, and the other end of this short arm 41 carries a peg 43 which is eccentric and is screw adjustable. For co-operation with the peg 43 there is a prop arm 44 pivoted on a shaft 45 and having a shoulder 44a directly underneath the peg 43. The prop arm 44 is connected by a link 46 to one end of a bell crank 47 the other end of which is connected by a link 48 to an arm 49 on a spindle 50 to which is also secured a control arm 51 having an end roller 52 for engagement by suitable studs of a control disc 53 on a disc control shaft 54.

There is also a latch 55 pivotally connected at 56 to the main needle bar 30 and operable through a link 57 connecting the latch 55 to a second bell crank lever 58 in front of the bell crank lever 47 and connected by link 59 to an arm 60 on a spindle 61 on which there is also secured an arm 62 having a roller 63 for engaging suitable studs on the control disc 53. The latch 55 has a catch 55a disposed immediately below the peg 39.

The disc shaft 54 is of known form in this type of machine and it is racked round by means of suitable ratchet mechanism under control of suitable bluffing mechanism in required manner to present suitable studs to control points for operating control arms as and when required. In the present instance the racking and bluffing of the control shaft 54 is effected in the manner and by the means disclosed in our patent No. 960,816 and US. No. 3,141,- 316 to which reference is directed for full details, and which briefly comprises the aforementioned programming means represented at 35 in FIGURE 2 whereby the suitable studs on the control disc 53 are presented at the cations of the rollers 52, 63 as and when required.

In operation of the split needle bar, and when producing plain fabric, the peg 39 will be clear of the catch 55a as shown in FIGURE 7, and the prop shoulder 44a will be clear of the peg 43, so that the normal knitting motion imparted to the main needle bar 30 through the arm 3 will be correspondingly imparted to the auxiliary needle bar 31 through the medium of the spring means 35.

When it is required to change to rib knitting, the opportunity is taken, before the last knock over action of the needle bars, for the prop shoulder 44a to be brought into position whereby as the needle bars descend, the short arm 41 is caused to rock about its pivot 42, whereby peg 39 is lowered to a level relatively to the latch 55 whereat the peg 39 engages at the underside of the catch 55a.

Thereafter during the following rib knitting, the auxiliary needle bar 31 is held down by the latch 55 in inoperative position.

Thus yarn will be fed only to the operative alternate frame needles thereby dispensing with the necessity for the aforesaid miss press points and associated mechanism.

The displacement of the prop catch 44a is of course elfected through its associated mechanism and the suitable stud on the control shaft 54 under control of the said programming mechanism, and when it is desired to again render the auxiliary needle bar effective, a further stud is arranged, again by the programming means, to release the latch 55, through its associated mechanism whereby the peg 39 can run to its original position with the auxiliary bar 31 effective through the spring means 35.

The free ends 270 of the latch guards 27 may have short extensions (not shown) projecting beyond the tips of the open latches, and to allow for the latches movements these extensions may be radiused, grooved, stepped, or cranked to project to one side of the latches, or the extensions may be bifurcated to extend on opposite sides of the latches.

What we claim is:

1. A straight bar plain knitting machine having spaced machine latch needles for enabling rib fabric to be produced, means for advancing the machine latch needles during which their latches are opened, and a latch guard for each machine latch needle to ensure that new yarn kinks, particularly when they are slack for forming slack loops, fall from the sinker noses onto the hook side of the latches, and means securing the latch guards in fixed relation to the machine needles.

2. A machine according to claim 1 wherein the latch guards are in the form of blade elements secured in the same tricks in the machine needle bed as the spaced machine needles.

3. A machine according to claim 1 wherein the latch guards are integral with loop spreader elements.

4. A machine according to claim 1 wherein the latch guards are secured to the needles.

5. A machine according to claim 1 wherein each machine latch needle has a shank and a stepped-down stem, and having a loop spreading element for each machine latch needle adapted for spreading a loop hanging rearwardly from the step of each machine latch needle.

6. A straight bar knitting machine having a frame needle bar, a row of bearded frame needles on the frame needle bar, a machine needle bar, a row of latch needles on the machine needle bar, said machine latch needles being spaced to correspond to alternate of the frame needles, cam operated means for imparting knitting movements to the frame needles, cam operated means for imparting knitting movements to the machine latch needles, a row of sinkers operable between the frame needles to sink yarn kinks between them and to relinquish spaced yarn kinks to the machine needles, a latch guard for each machine latch needle to ensure that new yarn kinks fall from the sinkers on to the hook side of the latches, and means securing the latch guards in fixed relation to the machine needles.

7. A straight bar knitting machine according to claim 6 wherein the frame needle bar is of split needle bar construction, and having control means for coupling the bars together and uncoupling them.

8. A machine comprising a split frame needle bar having two bars of frame needles, sinkers, a machine needle bar having spaced latch needles corresponding to alternate of the frame needles, means for operating the frame needles means for displacing the machine needles to be ineffective while plain fabric is produced on the frame needles, means for operating the machine needles, means for holding the frame needles in one of the frame needle bars down out of operation while rib fabric is produced on the machine needles and the frame needles of the other bar, means for feeding yarn to the operated alternate frame needles and onto the sinkers noses, a latch guard adapted to prevent yarn kinks from the sinker noses falling to the rear of the machine needle latches, means securing the latch guard in fixed relation to the machine needles, and a loop spreader adapted for holding machine needle loops spread for entry by rising frame needles.

9. A machine according to claim 8 having cam operated means connected to one bar of the split needle bar for imparting knitting movements to the frame needles of this one bar, means for coupling the other bar of the split needle bar to the one bar for operation therewith by said cam operated mechanism, and means for uncoupling the other bar from the one bar.

10. A machine according to claim 9 having control means operable when the split frame needle bar is at knock-over height for releasably latching one bar in operative position while the other bar continues with its knitting movements.

References Cited UNITED STATES PATENTS 2,957,324 10/ 1960 Willner 6688 XR 2,978,888 4/1961 Ladbrooke 66-88 3,050,967 8/1962 Taylor 6688 3,058,325 10/ 1962 Brown et a1. 6688 3,066,511 12/1962 Brooke 6688 3,111,828 11/1963 Brooke 6688 3,129,572 4/1964 Werner 66111 3,130,565 4/1964 Werner 6688 MERVIN STEIN, Primary Examiner.

R. FELDBAUM, Assistant Examiner. 

